1. Field of the Invention
This invention relates to check valves. More particularly, it relates to an oral inflation valve having an improved articulated connection between the valve stem and the valve head.
2. Description of the Prior Art
U.S. Pat. No. 5,135,025 to the present inventor represents the most pertinent prior art to the subject disclosure. That disclosure describes an oral inflation valve where a ball is formed at the leading end of a valve stem and where a socket for rotatably receiving the ball is formed in the valve head. The valve head skews when unseated by air passing through the valve, but the articulated connection between the head and valve stem ensures that the head will seat properly when the valve returns to its repose configuration under the influence of a bias means upon cessation of air flow therethrough.
In a second embodiment of the earlier device, a frustoconical member replaces the ball at the leading end of the valve stem, but the structure of the second embodiment is otherwise the same as the first.
Although both embodiments work well, it has been noted that the friction between the ball and socket tends to hold the valve head in a skewed position; the tension of the bias means employed to pull the valve head to its seated position must therefore be strong enough to overcome such friction. Moreover, it has been noted that the valve head, when unseated by air flowing therethrough, is extended from the valve body. In other words, when in repose the valve head is positioned at the distal end of the valve body, but when unseated it extends therefrom. Thus, the amount of skewing that may occur is quite high because the valve body provides no limitation thereto.
It has thus been perceived that the earlier device could be improved by eliminating the ball and socket connection between the valve head and valve stem, and by positioning the valve head within the valve body so that the body could serve to limit the amount skewing of the valve head when unseated from its seat by the passage of air through the valve body. However, this perception is part of the inventive process, and neither said perception nor the way to achieve the beneficial results of a design not subject to the limitations of the earlier design were apparent to those ordinary skill in this art at the time the present invention was made, in view of the prior art when considered as a whole at said time.